The invention relates to a vehicle seat which is pivotally movable between a use position and a stowed position.
In the case of a known vehicle seat of this type (DE 35 07 894 C2), rear legs of the vehicle seat are coupled by connecting rods so as to be forced to move with the pivoting movement of the seat cushion, a connecting rod being articulated on the front and rear leg on each side of the vehicle seat. In order that they can run smoothly during pivoting, articulations or pivot connections require a certain amount of play, this, of course, resulting in rattling noises which become more prominent as the service life increases and are extremely troublesome for the vehicle occupants. Such rattling noises can be avoided only by high-outlay structural damping measures. Moreover, such a connecting-rod system may take up positions in the vicinity of the dead center, this resulting in sluggishness and jamming and being avoidable only with additional outlay in terms of design.
An object of the invention is, in the case of the vehicle seat of the type mentioned in the introduction, to specify a cost-effective design solution for automatically folding the rear legs onto the seat frame when the seat cushion is pivoted upwards, said solution being free of jamming and also still being absolutely free of rattling even after a relatively long operating period of the motor vehicle.
This object is achieved according to the invention, by providing a vehicle seat comprising
a seat cushion including a seat frame and seat upholstery, PA1 a backrest pivotally supported on the seat frame to be foldable over onto the seat upholstery when the seat is in a stowed position, PA1 pairs of downwardly projecting front and rear legs pivotally connected to the seat frame and serving to fasten the seat frame on a vehicle floor, said rear legs being releasably lockable on the floor to accommodate upward pivoting movement of the seat cushion, PA1 a first belt pulley arranged coaxially with respect to a pivot connection of the front legs on the seat frame and connected in a rotationally fixed manner to at lest one front leg, PA1 a second belt pulley arranged coaxially with respect to a pivot connection of the rear legs on the seat frame and connected in a rotationally fixed manner to at least one rear leg, PA1 and a drive belt connecting the first and second belt pulleys such that the rear legs are forced to move to a stowed position when the seat cushion is pivoted upwardly to a seat stowed position.
In the case of the vehicle seat according to the invention, the rear legs are forced to fold onto the seat frame when the seat cushion is pivoted upwards in order to provide free space by means of belt pulleys. The belt pulleys are connected in a rotationally fixed and thus rattle-free manner to the front and rear legs. At least one drive belt connects the belt pulleys to one another and consists of a flexurally soft material and likewise does not cause any rattling noises even in the event of decreasing tensioning in the belt. The belt pulleys and drive belts are manufactured from plastic, preferably as injection-molded parts, and can thus be produced inexpensively, with the result that the design solution according to the invention is also appropriately priced for small, inexpensive motor vehicles.
The pivoting structure according to the invention can be just as advantageously used in the case of lower seats with a small spacing of the seat cushion from the vehicle floor as with high seats with a considerable amount of clearance beneath the seat cushion.
According to an advantageous embodiment of the invention, the drive belt is preferably of an endless design, e.g., designed as a toothed belt or V-belt or as a flat belt consisting of a tension-resistant, flexurally soft material.
Since the pivoting angle of the belt pulleys is smaller than the loop-around angle of the drive belt, the drive belt can be fixed on the belt pulleys, provision being made for this in a preferred embodiment of the invention. Consequently, slippage between the drive belt and the belt pulleys is avoided, even in the event of material fatigue of the drive belt, and precise, play-free pivoting of the rear legs into their position in which they are folded on the seat frame, and vice versa, is always achieved.
Due to the small pivoting angle of the belt pulleys, the drive belt may also, according to an alternative embodiment of the invention, be of an open-ended design and be fastened, by in each case one end, on the circumference of the belt pulleys by fastening means. Instead of the drive belt, use may also be made of a cable pull or of another non-rigid connection means which transmits a tensile force.
In a preferred embodiment of the invention, at least one of the two belt pulleys has a contour in the case of which the spacing of the circumference line from the center point which is coaxial with the pivot pin of the legs changes constantly at least over a range of angles at the circumference. In this arrangement, the belt pulley is aligned such that the maximum spacing of the circumference line from the center point coincides with the line of connection which passes through the pivot pins of the rear and front legs, locked on the vehicle floor, on the seat frame. This type of design makes it possible to achieve a rear-leg movement sequence in which, at the beginning of the pivoting operation, the rear legs first of all remain unaffected, and can thus be lifted out of the anchor region of the vehicle floor in a virtually rectilinear manner, and start to fold onto the seat frame only after a considerable pivoting movement of the seat cushion.